The present invention relates to an ultrasonic washing apparatus in which a flat face or a curved face of a disc is washed by ultrasonic vibration transmitted through a rod horn.
In an ultrasonic disc washing apparatus according to the prior art, a wedge material is formed by a flat face paralleled with a disc to be washed, an upper face formed by a little angle to the flat face and a back face formed between the flat face and the upper face having an angle of 50 to 80 degrees to the flat face. An ultrasonic vibrator connected to an oscillating circuit is attached to the back face of the wedge, and a washing liquid applying device is provided which includes a nozzle for applying a washing liquid.
In the ultrasonic disk washing apparatus in the prior art, the wedge material or the disk to be washed is moved, and the washing liquid is applied by the nozzle between the flat face of the wedge and the face of the disk to be washed. When an oscillating power is applied to the ultrasonic vibrator, ultrasonic waves generated by the ultrasonic vibrator are transmitted from the back face of the wedge materials through the flat face of the wedge material to the washing liquid on the disk to be washed, and the face of the disk to be washed is washed by the washing liquid.
In the above ultrasonic washing apparatus, the ultrasonic vibration generated by the ultrasonic vibrator is transmitted from the back face of the wedge material through the flat face to the washing liquid on the surface of the disk to be washed and the surface of the disk to be washed is washed by the ultrasonic vibration transmitted to the washing liquid, Then, because focusing position (focusing point) of the ultrasonic wave generated by the ultrasonic vibrator is put on the position of the flat face of the wedge material determined by the form of the ultrasonic vibrator and frequencies of the ultrasonic waves, damage is added to minute patterns on a semiconductor by the irradiation of the focused ultrasonic vibration to a semiconductor having a minute pattern and the patterns of the semiconductor are destroyed by the focused ultrasonic vibration.
It is provided that a prior ultrasonic washing apparatus has the edge material forming a perforation hole in the side face. However, in the prior ultrasonic washing apparatus, the formation of the edge material becomes complicated, the washing liquid and contamination are accumulated in the perforation hole and this becomes a cause generating particles marring the disk of the semiconductor.